Adjustment device for helmet strap



FIG. 1 is a perspective view of an “adjustment device for helmet strap” showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

It being understood that the broken lines are for exemplary illustrative purposes only and form no part of the claimed design. 

The ornamental design for an “adjustment device for helmet strap,” as shown and described. 